Fix: UndefVarError in get_norm_matrix for BlockProjection

src/RB/RBSteady/Projections.jl

@@ -719,6 +719,9 @@ for f in (:project!,:inv_project!)
 end
 
 function Arrays.return_cache(::typeof(get_norm_matrix),a::BlockProjection)
+  blocksizes = num_fe_dofs(a)
+  n = sum(blocksizes)
+  norm_matrix = BlockArray(zeros(n,n),blocksizes,blocksizes)
   i = findfirst(a.touched)
   @notimplementedif isnothing(i)
   A = typeof(get_norm_matrix(a[i]))

test/RBSteady/block_projection_norm_matrix.jl

@@ -0,0 +1,28 @@
+module BlockProjectionNormMatrixTest
+
+using Test
+using GridapROMs
+using GridapROMs.RBSteady
+using BlockArrays
+using LinearAlgebra
+
+function main()
+  basis1 = rand(10,3)
+  basis2 = rand(10,2)
+  proj1 = PODProjection(basis1)
+  proj2 = PODProjection(basis2)
+
+  array = [proj1,proj2]
+  touched = [true,true]
+  bp = BlockProjection(array,touched)
+
+  norm_matrix = get_norm_matrix(bp)
+  @test norm_matrix isa AbstractMatrix
+  @test size(norm_matrix) == (20,20)
+  @test norm_matrix[Block(1,1)] == I(10)
+  @test norm_matrix[Block(2,2)] == I(10)
+end
+
+main()
+
+end